Abstract

Heterostructures of grown by hydride vapor phase epitaxy(HVPE) and molecular-beam epitaxy(MBE) are characterized with the current–voltage , capacitance–voltage , and deep level transient spectroscopy(DLTS) techniques. Using different contact configurations, the results reveal a rectifying barrier in the heterostructures. When GaN is negatively biased, the current is exponentially proportional to the applied voltage with the built-in barrier being for the HVPE samples and for the MBE sample. DLTS measurements reveal intense band-like deep level states in the interfacial region of the heterostructure, and the Fermi-level pinning by these deep level defects is invoked to account for the interfacial rectifying barrier of the heterostructures.